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L. 0. MACRAE AND P. A. MAcEACHERNt SETTLING TANK- APPLICATION FILED NOV. 29.1918. '1 ,3 1 3, 71 4 Patented Aug. 19, 1919.

2 SHEETS-SHEET I.

Pete r fl. maaEaohw'm A TTOR/VEYS L. D. MAcRAE AND P. A. MACEACHERN.

SETTLING TANK.

APPLICA ION FILED NOV-29.1918.

1 ,3 1 3, 7 1 4: Patented Aug. 19, 1919.

2 SHEETSSHEET 2.

, WITNESSES 76 u. INVENTORJ L m hLLnJD. MaolZae, Pet er -21. may ha m ,4 ITORNEVS UNITED STATES PATENT OFFICE.

LACHLIN DONALD MAORAE AND PETER A. MAOEACHERN, OF NACOZARI, MEXICO.

SETTLING-TANK.

Specification of Letters Patent.

Patented Aug. 19, 1919.

Application filed November 29, 1918. Serial No. 264,701.

To all whom it may concern:

Be it known that we, LACHLIN D. MAC- RAE and PETER A. MACEACHERN, citizens of the United States, and residents of Nacozari, Sonora, Mexico, have invented certain new and useful Improvements in Settling- Tanks, of which the following is a speci cation.

Our invention is an improvement in settling tanks, and has for its object to provide a device of the character specified especially adapted for use in flotation plants and. ore dressing plants for settling slimes and for skimming and settling flotation concentrates, wherein a tank is provided having separate launders for the clear solution and the froth and having means for skimming the contents of the tank and directing the froth into the froth launder.

In the drawings:

Figure 1 is a top plan view of the improved tank;

Fig. 2 is a section on the line 22, looking in the direction of the arrows adjacent to the line;

Fig. 3 is an enlarged view of the cleaner launder.

In the present embodiment of the invention, a tank 1 is provided, of usual construction and of circular cross section having in the wall thereof a pulp discharge opening 2, from which leads a discharge pipe 3. A second tank 4 is supported within the tank 1 concentric therewith, the said tank 4 having both ends open, as shown, and being secured to a shaft 5, which is mounted for rotation in a truss construction 6 arranged above the tank 1.

This shaft is rotated by means of a shaft 6 driven by a belt 7 from a suitable source of power, and connected to the shaft 5 by means of gearing indicated at 8. The tank 4 is connected to the shaft 5 at the bottom of the tank by a spider 9, and at its top a sweep 10 extends from the shaft in opposite directions, the said sweep carrying depending skimmers 11 which may be of any suitable material, as, for instance, flexible belting.

The sweep is supported atits ends by a railing 12, and the sweep has rollers 13 journaled on its under face at its ends and running upon the rail. The rail is supported from the inner edge of a clear solution overflow launder 14, which has in connection therewith a take-off 15 leading to a suitable place of discharge. The skimmers 11 depend into the solution a sufficient distance to sweep up the froth and carry the same into the froth launder 16 which, as shown more clearly in Fig. 1, extends radially from near the outer surface of the tank 4 to and through the wall of the tank 1, where it delivers to the take-off 2 for the, froth, the said take-off delivering at a suitable point of discharge. The launder 16 is braced by inclined braces 17, and the rail 12 is supported by a ring 18, and by radial wings 19 on the inner wall of the launder 14.

Referring to Fig. 1, it will be seen that the gearing 8 is a worm gear connection, the worm being on the shaft 6, and the gear wheel on the shaft 5. The shaft 6 has a pulley 20 which the belt 7 engages, and the material is fed to the tank through a feed or loading launder 21.

In operation, the tank is loaded or charged from the launder 21, which delivers to the tank 4. The solution holding in suspension the slimes or other material is restricted in its movement by the wall of the tank 4, thereby diminishing the agitation of the solution in the tank 1. Also by impounding the dense solution-in the tank 4, the greater portion of the coarse or heavy material is deposited at or near the center of the tank 1. Since the solution must pass through the bottom of the tank 4 to reach the tank 1 the very fine material will traverse a longer path before the solution reaches its 'final discharge point at the launder 14. When the shaft 5 is in motion, as it is during the operation, thereby rotating the sweeps 10, which carry the skimmers 11, the surface of the solution in the tank 1 is cleared of froth and the like by the skimmers, and this froth is discharged into the launder 16. The arrangement is especially applicable in flotation plants and ore dressing plants for settling slimes and for skimming and settling flotation concentrates.

We claim:

1. A device of the character specified comprising a circular tank having a discharge opening at the center of the bottom, a shaft journaled at the axis of the tank, means for rotating the same, said shaft having op- 1 vide unhindered settling of the solution withsitely extending skimmer rotating therewith, in the bottomless tank, the skimmers extendand supporting a bottomless tank coaxial ing between the bottomless tank Wall and with the main tank and depending from near 15 the main tank, means for feeding the matethe bottom of the other tank and spaced 5 rial to be settled to the bottomless tank, and apart from the said bottom to provide ung a froth launder to which the Skimmers dehindered settling of the solution Within the;

1 liver. bottomless tank, the skimmers extending be' 2. A device of the character specified comtween the bottomless tank Wall and the main 20 prising a circular tank having a dischargetank wall.

10 opening at the center of the bottom, a shaft 1 journaled at the axis of the tank, means for LACHLIN DONALD MACRAE. rotating the same, said shaft having opno- PETER- A. MAoEACHER-N. 

